llvm dev - Sep 2018 - [RFR] JDK-8156980: Hotspot build doesn't have -std=gnu++98 gcc option

Hi Martin,

Thanks for your response!

I haven't tested compiling OpenJDK 12-dev with LLVM toolchain, perhaps 
the issue had been fixed already,  because clang treat invalid argument 
'-std=gnu++98' not allowed with 'C' as error.  It is better only
apply
EXTRA_CFLAGS to C without EXTRA_CXXFLAGS.

Furthermore, I just have interest, did you use clang analyzer, sanitizer 
and libfuzzer towards hotspot and jdk native library? Thanks!

在 2018年09月06日 02:10, Martin Buchholz 写道:
> We seem to have some confusion about flags for C vs. flags for C++.  
> Most flags for most toolchains apply to both C and C++, so it's 
> understandable that we want to unify them.  But some flags, notably 
> -std, are language-specific.  We have both EXTRA_CFLAGS and 
> EXTRA_CXXFLAGS, so we should expect EXTRA_CFLAGS to only apply to C.
-- 
Regards,
Leslie Zhai

it's difficult to use llvm tools like sanitizers on openjdk sources,
because of the "cheating" - relying on undefined behavior, and the
JIT.

On Wed, Sep 5, 2018 at 6:09 PM, Leslie Zhai <zhaixiang at loongson.cn>
wrote:
> Hi Martin,
>
> Thanks for your response!
>
> I haven't tested compiling OpenJDK 12-dev with LLVM toolchain, perhaps
the
> issue had been fixed already,  because clang treat invalid argument
> '-std=gnu++98' not allowed with 'C' as error.  It is better
only apply
> EXTRA_CFLAGS to C without EXTRA_CXXFLAGS.
>
> Furthermore, I just have interest, did you use clang analyzer, sanitizer
> and libfuzzer towards hotspot and jdk native library? Thanks!
>
>
> 在 2018年09月06日 02:10, Martin Buchholz 写道:
>
>> We seem to have some confusion about flags for C vs. flags for C++. 
Most
>> flags for most toolchains apply to both C and C++, so it's
understandable
>> that we want to unify them.  But some flags, notably -std, are
>> language-specific.  We have both EXTRA_CFLAGS and EXTRA_CXXFLAGS, so we
>> should expect EXTRA_CFLAGS to only apply to C.
>>
>
> --
> Regards,
> Leslie Zhai
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20180905/fd436f2d/attachment-0001.html>

It might be UBSan false positive :) What about ASan? 
https://bugs.openjdk.java.net/browse/JDK-8189800


在 2018年09月06日 09:12, Martin Buchholz 写道:
> it's difficult to use llvm tools like sanitizers on openjdk sources, 
> because of the "cheating" - relying on undefined behavior, and
the JIT.
>
> On Wed, Sep 5, 2018 at 6:09 PM, Leslie Zhai <zhaixiang at loongson.cn 
> <mailto:zhaixiang at loongson.cn>> wrote:
>
>     Hi Martin,
>
>     Thanks for your response!
>
>     I haven't tested compiling OpenJDK 12-dev with LLVM toolchain,
>     perhaps the issue had been fixed already, because clang treat
>     invalid argument '-std=gnu++98' not allowed with 'C' as
error.  It
>     is better only apply EXTRA_CFLAGS to C without EXTRA_CXXFLAGS.
>
>     Furthermore, I just have interest, did you use clang analyzer,
>     sanitizer and libfuzzer towards hotspot and jdk native library?
>     Thanks!
>
>
>     在 2018年09月06日 02:10, Martin Buchholz 写道:
>
>         We seem to have some confusion about flags for C vs. flags for
>         C++.  Most flags for most toolchains apply to both C and C++,
>         so it's understandable that we want to unify them.  But some
>         flags, notably -std, are language-specific.  We have both
>         EXTRA_CFLAGS and EXTRA_CXXFLAGS, so we should expect
>         EXTRA_CFLAGS to only apply to C.
>
>
>     -- 
>     Regards,
>     Leslie Zhai
>
>
>
-- 
Regards,
Leslie Zhai